feat: add mysql offline store

[jerempy]

Description

Adds mySQL as offline store

There are some aspects of mySQL that differ from postgresql. For example mySQL doesn't have materialized views. But the offlinestore interface has several methods centered around materialized views. I incorporated simiarl/close to functionality with mySQL views - but it just not exactly the same. Where possible got close approximations of the behavior of the interface methods and did implement all methods to satisfy the interface definition.

Type of change

Feature: Include mySQL and the go mySQL driver as option for offline store

Does this correspond to an open issue?

Closes: #1069

Select type(s) of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

Checklist:

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have fixed any merge conflicts

[simba-git]

Thanks for the PR!

[omarshanti-mfp]

Bug?